1. Field of the Invention
The invention relates to novel surfactants and drying, drycleaning and soil repellency compositions which utilize such surfactants. More particularly, the invention relates to fluorine containing surfactants, and drying, drycleaning and soil repellency compositions which contain at least one halocarbon solvent component and at least one fluorine containing surfactant. Such compositions have the ability to remove water or aqueous films from the surfaces of a broad range of substrates and impart soil repellency to fabrics.
2. Description of the Prior Art
Many industries use aqueous compositions for the surface treatment of metals, ceramics, glass, and plastics. Cleaning, plating, and deposition of coatings is often carried out in aqueous media but must be followed by a drying step. Hot air drying, centrifugal drying, and solvent-based water displacement are among the methods used. While hot air drying is commonly used to remove water from the work, the high energy requirement to heat air results in a significant expense. A variety of solvent-surfactant drying compositions for water displacement are also well known to those skilled in the art. The advent of certain hydrofluorocarbons (HFC's) allows the industry to utilize vapor degreasing and its advantages of low energy requirements, flash drying, recyclability, and high throughput. Drying compositions based on trichloroethylene or chlorofluorocarbon-113 have been used. However, concerns due to toxicity and environmental acceptability have led to a decline in the use of such systems.
HFC solvent containing drying compositions are known in the art. Illustrative of such compositions are those described in U.S. Pat. Nos. 4,438,026 and 4,401,584 which are incorporated herein by reference. These compositions remove water from a substrate by displacement. Many HFC's have the disadvantage of limited solvency for hydrocarbon oils and fluxes and the use of surfactants is important in many applications. Halocarbons and a properly selected hydrophobic surfactant can be used to displace water from water laden work. However, the identification of the appropriate surfactants to accomplish water displacement is not trivial. Drycleaning and drying or water displacement require surfactants that impart distinct properties to solvent mixtures. For removing oils from machined metal parts, a surfactant aids in removal of soils that would otherwise be only sparingly soluble in a hydrofluorocarbons. Water displacement requires a surfactant that does not form a stable emulsion with water.
In addition, just as many hydrofluorocarbons are unable to dissolve many soils, they are unable to dissolve a number of surfactants. Therefore, one must not only identify those surfactants which are soluble in the HFC, but also those having the desired activity in the HFC. Furthermore, there are differences among the classes of surfactants, e.g., anionic versus cationic, among surfactants within a class, e.g., the presence or absence of a sulfide linkage, and even among similar surfactants that only differ in chain length. It has been a problem in the art to find a hydrophobic surfactant that is essentially insoluble in water, will not form an emulsion with water and yet is still able to displace water from a variety of surfaces.
It has now been found that by the use of the inventive surfactant, the performance of HFC's in drying, drycleaning and soil repellency composition is enhanced. The invention has found a new class of HFC soluble hydrophobic fluoro-surfactants with surface activity in the HFC that is useful to displace water. More particularly, the composition of this invention comprises one or more organic halocarbons and an effective amount of one or more fluorine containing quaternary ammonium salts.
The solvent drying composition of the invention is very effective in displacing water from a broad range of substrates including metals, such as stainless steel, aluminum alloys, brass and the like; and from glass and ceramic surfaces, such as glass, borosilicate glass, unglazed alumina, silica such as silicon wafers used in miniaturized electronic circuits, fired alumina and the like. The compositions of the invention do not form noticeable emulsions with the displaced water or form insignificant amounts of such emulsion.
In another embodiment of the invention, there is provided a novel surfactant-solvent composition and a process for treating fabric to impart soil repellency. The surfactant-solvent composition promotes soil removal, and when present in a rinse stage imparts oil repellency. It is an important feature of this invention that the surfactant contain at least one aromatic substituent in a cationic quaternary ammonium moiety. Because of the presence of the fluorinated substituent or substituents, these materials are soluble in the halocarbon, thus forming substantially homogeneous compositions, and can displace water from a broad range of substrates and aid in the removal of soils from fabric.